In the homemade, "true story" vein of Blair Witch Project, (the hype scared away the scares for me in that one) Paranormal Activity is about a young couple who live in a butt-ugly generic house in San Diego, where things go bump in the night. Willing to find out what's making the strange noises, the guy (there are no credits in the movie), a classic immature American alpha nerd, trains his video camera on the house and leaves it on all the time. I enjoyed the two actors, particularly the girl, who exhibits the wise, warm patience of females towards maturity-challenged boyfriends. The actors had an easy, realistic intimacy that is seldom seen in the genre. I wish the writer-director Oren Peli had not wasted the opportunity to show more of the strains in the relationship, which would have added extra tension and made it even worse. I wish he had given more psychological nuance and drama to the couple.
Most of the time the movie just waits for the malevolence to appear. Part of its success is that it builds up the tension really slowly. Of course, five minutes into the creepiness, the first thought in one's mind is "Get your ass to the nearest Holiday Inn, you idiots", but the script establishes that even if they sleep elsewhere, the malevolence will follow. Neat and stupid, but it kind of works. That's what happens when you deal with demons, they can break the rules of logic.
The flat, creepy monotone of the video camera captures the malevolent presence by its stealthiness. Most of it you can't see, but you can see its effects. This is scary. Watching it through the video somehow heightens the creepiness, even though more than once the audience has to watch the footage twice, as its being recorded, and as the couple checks it in the morning. Since we are watching footage of what happened during the night, we are put in the position of the protagonists, who go to sleep at night (I don't understand how they manage to do this) and wait until morning to check what the camera recorded. There is a lot of dead time that seems to serve no purpose, but because of the premise the movie is forced to work with this constraint. There are some very creepy moments, and some well delivered bolts, classic of the genre, which are absolutely delightful. The audience jumps and screams and then laughs at itself. The night I saw it at Lincoln Center, the teenager sitting in front of me kept protecting himself from the movie with his hoodie, which was worth the price of admission. There are a couple of beautifully rendered scares and I loved the creepy non-credit sequence in the end. What is very likable about this movie is that it's made with a very low budget but lots of ingenuity, a great imaginative resourcefulness that does not depend on expensive CGI or special effect toys to make its scary point. It is still amazing that a simple door ajar or some unexplained footprints or some inexplicable noises can make the hair in the back of your neck stand on end.